Gun charger



Oct. 22, 1946. H. c. GRANT, JR

GUN CHARGER Filed Nov. 14, 1941 .4 Sheets-Sheet l M22/r BY ATTORNEY t. 22, i946. H. c. GRANT, JR 2,409,623

GUN CHARGER Filed Nova, 14; 1941 4 sheets-sheet a INVENTOR Hmz? .*dzzdr BY ATToRN Oct. 22, 1946;

H. c. GRAN-lv', JR A 2,409,623

GUN CHARGER Filed Nov. 14, 1941 4 sheets-sheet 4 ATTORN Patented ct. 22, 1946 man?.

GUN CHARGER Harry C. Grant, Jr., New York, N. Y., assignor to I Specialties Development Corporation, Bloomfield, N. J., a corporation of New Jersey Application November 14, 1941, Serial No. 419,053

8 Claims.

The present invention relates to automatic mato devices, known as gun chargers, for initiating the operation of a gun charging mechanism which normally is operated by the recoil resulting from the explosion of cartridges.

In automatic machine guns, for example, of the Browning type, release of the ring pin, either mechanically or electrically, fires a cartridge in the chamber of the barrel of the gun. The resulting recoil causes a bolt mechanism or charging mechanism to move backward to withdraw the exploded or fired cartridge case and, at the same time, to present a Succeeding cartridge on a cartridge feed belt adapted to be fed into the chamber. After the bolt mechanism has been fully retracted, it returns to the iiring position and in the course of its return stroke ejects the empty or iired cartridge case and feeds the succeeding cartridge into the chamber. While the firing pin is released, the gun iires when the bolt returns to the full forward position. If no trouble develops, the cycle of operation of the charging mechanism is repeated at a rate of between about 400 and 1G00 shots per minute.

Once the gun has been loaded, iiring should be automatic unless any one of a number of possible difculties occurs. For example, a shell may fail to explode or may fail to develop a recoil force sufficient to move the bolt mechanism through the shell ejecting and loading cycle. Also, the charging mechanism may fail to extract the cartridge from the belt or a shell may jam in the barrel and resist removal on the rst attempt. In addition, any one of the many elements of the bolt or charging mechanism may fail momentarily to perform its designed function and prevent the ejecting and loading cycle from being properly performed. In the event that the bolt or charging mechanism fails to function properly for any of the foregoing reasons, it is necessary to pull the bolt mechanism fully backward and then release it-to complete the ejecting and reloading operation normally carried out by the gun itself after it has once been red.

Heretofore, devices known as gun chargers have been employed for mechanically actuating the charging mechanism in response to failure of the gun to continue firing. None of these devices has been found fully satisfactory because of the complexity of design, unreliability of performance and relatively long delay occasioned before putting the gun into action again.

The present invention aims to provide an irnproved, practical, and reliable gun charging device which is accurately controlled, can stand rough usage and is adapted to return the gun to ring action in a minimum period of time.

An object of the present invention is to provide an improved gun charger which is light in weight and occupies a amount of space.

Another object is to provide a gun charger having a minimum number of mechanical parts.

Another object is to provide a gun charger adapted to be mounted on either side of a inachine gun, as may be decided in the eld or prior to the installation of the guns in airplanes, tanks or other craft.

Another object is to provide a gun charger which is readily adjustable to compensate for variance in the stroke of the guns, whereby the gun charger may be transferred from one gun to another.

Another object is to provide a gun charger having a minimum number of parts which are in operation while the gun is firing normally.

Another `object is to provide a gun charger adapted to be operated by a high pressure fluid Another object is to provide an accurate detecting mechanism for gun chargers and the like which can withstand shock and vibrations Without getting out of adjustment or repair.

Another object is to provide an electrically operated detecting mechanism comprising a minimum number of parts, electrical connections and wiring circuits.

Another object is to provide a detecting mechanism for gun chargers which operates in respense to failure of the gun to fire regardless of the position of the bolt or charging mechanism when stoppage occurs.

Another object is to provide a gun charger adapted to operate the bolt or charging mechanism through at least one complete cycle of operation- Another object is to provide a gun charger having a detecting mechanism adapted to put the gun charger back into operation within substantially the same period of time required for one cycle of operation of the gun, whereby the gun remains` out` of action a minimum length of time.

A further object is to provide a gun charger havinCf a detecting mechanism adapted to be cut out of operation when the gun charger initiates operation of the bolt or charging mechanism and adapted to remain out of operation until the gun is restored to normal firing operation.

Other and further objects, not specifically enumerated above, will be apparent when described in greater detail in connection with the accompanying drawings, wherein:

Figure 1 is a diagrammatic side view of a machine gun having a gun charger attached thereto.

Figure 2 is a schematic View of the essential operating parts of a gun charger, illustrating an embodiment of the invention.

Figure 3 is a wiring diagram of the electrical circuits of a gun charger, in accordance with the invention.

Figures i and 5 are simplied wiring diagrams, illustrating the operation of the detecting mechanism of the gun charger.

Figure 6 is a simplied Wiring diagram, similar to Figures i and 5, illustrating the detecting mechanism cut out of operation while the gun charger moves the bolt or charging mechanism.

Figures 7, 8 and 9 are simplified wiring diagrams, illustrating a modified circuit for the detecting mechanism of the gun charger.

In accordance with the invention, it has been found that the foregoing objects may be accomplis'hed by providing a detecting and initiating device, suitabie for machine guns and other purposes, having electrical detecting and controlling means which is operable in response toa current pulse of a predetermined minimum time interval, and which is not aiected'by current pulses of less than the minimum time interval.

In a .practical embodiment, illustrative of the invention, such a device, generally, may comprise a circuit supplied with a continuous current from a direct current source; relay means or the like connected in the circuit, the relay means being constructed and arranged to be actuated by a current rpulse of a predetermined minimum time interval in either direction, but being unaffected by current pulses f less than Vthe minimum time interval; and means associated with the bolt or charging mechanism of a machine gun for periodically interrupting the continuity of a portion o vthe circuit, whereby the relay means is subjected to current pulses of less than the minimum V time interval during normal movement of the bolt or charging mechanism, Thus the relay means, during continuous iiring of the gun, is not affected by the periodically interrupted current or current pulses of less than the minimum Vtime interval, but upon failure of normal movement of the bolt or charging mechanism, the interruption of the current ceases for a suicient duration to permit current of a substantially continuous character or a current pulse of the minimum time interval to energize the relay means and effect operation thereof. The invention further contemplates the use of such a detecting and controlling device in combination with a fluid pressureV operated ram for mechanically moving the charging mechanism through its operating cycle. In addition, the gun charger may be provided with means for rendering the detecting and controlling device inefective when the ram commences to function and may be provided with other cooperating devices and improvements which will 'be pointed out more particularly hereinafter.

Referring to the drawings, and more particularly to Figure l, there is shown a machine gun, for example, of the Browning type which, generally, comprises a barrel assembly lll and a bolt mechanism or charging mechanism (not shown), which is located in a housing or casing Il. The charging mechanism is of the usual design and includes a number of slidably movable or reciprocating parts which are moved rearwardly by the recoil resulting from the explo-sion of cartridges and which are moved forwardly by a return spring or the like. During reciprocation of these parts, the operating cycle of the gun is carried out. This cycle comprises removing a cartridge from the cartridge belt and inserting it into the chamber, firing the cartridge, withdrawing the fired cartridge from the chamber and ejecting the empty cartridge case from the housing ll. Since the construction and operation of such a charging mechanism is well known to those skilled in the art, a detailed illustration and description is not believed to be necessary.

In the event the normal operating or iiring cycle of the gun is interrupted and iiring ceases,

, the gun must be recharged or recocked before it can be put in operation again, To accomplish this, a gun charger l2, suitably encased, may be attached to either side of the gun housing H and may be operatively connected to the bolt or charging mechanism by a bolt or stud member hl which extends through an elongated slot l5 in the housing l! and is movable with the reciprocating parts of the charging mechanisml The gun charger l2 preferably is operated by a fluid pressure medium, such as high pressure carbon dioxide, air or any suitable gas stored in a pressure vessel I6 and adapted to be supplied to the gun charger by a hose or tube l1. A cable i8 containing electrical conductors for the electrical devices of the gun charger is attached to one end of the gun charger.

In Figure 2, the essential operating parts of the gun charger are illustrated schematically. The reciprocating bolt or stud member E4 or the gun charging mechanism is shown adjacent and in the path or a ram E9, or tl e like, adapted to engage the member 615 and move it towards the left along the slot l5, that is, rearwardly with respect to the gun, in the event the gun ceases ring during operation thereof. The ram i0 comprises a cylinder 2Q and a slidable member 2l adapted to be telescoped in the cylinder 2i?. The member 2l has a piston 22 at one end and a ramming head 24 at the other end for moving the bolt or stud member it.

The ramming head 2t has a recessed end face 25 for engaging an adjustable stop 26 threaded through the bolt or stud ifi. The stop 25 may be utilized to accurately determine the distance the bolt or stud i/l and the slidable parts of the charging mechanism can be moved rearwardly by the ram. The ramming head may be slidably mounted on a pairV of spaced apart parallel guide tubes or rods 2.7 which extend respectively through guide apertures in outwardly extending lugs or ears 29 carried by the head 2li. One of the lugs 29 of the head 24 may have a downwardly depending extension 3B provided with a pair of arms 3l and 32 which .extend in a direction parallel to the movement of the head and are adapted to operate devices described hereinafter.

The slidable ram Vmember 2l, preferably, is moved out of the cylinder 2D bysupplying a iiuid pressure medium in back of 'the .piston 22 and is returned to the position shown in Figure 2 by suitable springs 34. A valve 35 is utilized to conjtrol the admission and the exhaust of the pressure medium to and from the cylinder. This valve may comprise a body having a chamber therein; a valve seat 36 in communication with thechamber and an inletport 3l connected to the pressure medium supply hose Il; a second valve seat 38 in communication with the chamber and an exhaust port 33; a valve member 40 in the chamber; and a conduit 4I leading from the chamber to the cylinder 2B. When the valve member 45 abuts the seat 35, the inlet port 3'.' is shut off and the exhaust port 35 is open to enable pres-sure medium in the cylinder 20 to escape, whereby the springs 34 may rapidly return the slidable member 2l to the position shown .in Figure 2. When the valve member 45 is moved towards the right and abuts the seat 39, the exhaust port is closed and the inlet port is opened to admit pressure medium to the cylinder. The valve member 4i! is provided with a stem 42 extending outwardly through the valve body and adapted to be engaged by a suitable valve controlling device about to be described.

The device for controlling the valve may comprise an arm or linger 44, for engaging the valve stem 42 which is mounted on one end of a slidable rod 45 extending through one of the tubuu lar guides 2l; a lever 46 pivoted at 4l and having the other end of the rod 45 connected thereto at 45; and a spring operated device connected to the other end of the lever 45. The spring operated device may comprise a tubular collar 55 pivotally connected to the lever 45 at 5I; a slidable bai or rod 52 extending through the collar 5l! and limited for sliding movement with respect thereto by a ange 54; and a cylindrical helical spring 55 which is telescoped about the rod 52 and is compressed between a ange 56 adjacent one end of the rod 52 and the collar 55. The end of the rod 52 adjacent the ilange 55 has one end of a. tension 'spring 5l attached thereto and the other end of the spring is secured to a suitable fixed point at 59. 'I'he other end of the rod 52 is provided with a projection, tooth, or dog 5G adapted to be engaged by a projection 5I on a latching lever 52 pivotally mounted at 64.

When the projections 60 and 6l are in engagement, the spring 55 is compressively loaded and bears against the collar 50 to swing the lever 45 in a direction to slide the rod 45 into a position whereby the finger 44 holds the valve stem 42 to cause the valve member 4G to close the inlet port 37. The projections C55 and 5I may be unlatched by a solenoid 65 or other suitable device to be actuated when movement of the ram is desired. When the projections 54 and Si are unlatched, the spring 55 expands, and the rod 52 slides within the collar 5E! to a position lwhere the flange 54 abuts the collar 55 and the spring 55 has no effect on the lever 45. The spring 5l then pulls the rod 52 to 'swing the lever 45 into the position, indicated by the broken line (denotingthe longitudinal axis of the lever), and the lever moves the rod 45 to enable the linger 44 to release the valve stem 42. Movement of the rod 45 may be further assisted by a spring 66 attached to the end thereof or to the finger 44. Preferably, the lever 46 is latched in this position by a latch member 5l carried by the lever and having a projection 69 adapted to engage a xed litch projection l0.

i When the stem 42 is released, the pressure of the pressure medium moves the valve member 4I) away from the seat 36 and the pressure rneengages the stop 26 of the bolt'l or stud I4k wherever it may be along the slot I 5, and moves the bolt I4 and the reciprocating parts of the charging mechanism to their extreme rearward or leftward position.

When the ramming head approaches its rearmost position, it is desired to shut off the supply of pressure medium and exhaust the cylinder. This is accomplished by the arm 3l which engages, for example, the ilange 56 of the rod 52 and pushes the rod through the collar 55 to reload the spring 55 and cause the projections 60 and 6I to reengage. Upon further movement of the head 24, .the slightly shorter arm 32 comes in contact with the latch memberV 6l and releases the projection 69 from the projection 74. This enables the spring 55 to swing the lever 45 into its initial position, whereby the rod 45 is moved to cause the nger 44 to operate the valve stem 42 which in turn causes the valve member to close the inlet port 3l and open the exhaust port 35. The sudden exhaust of the fluid pressure medium from the cylinder enables the springs 34, which are relatively strong, to return the ram member 2i and its associated parts to their forward position.

It will be understood that, while an illustrative embodiment of a device or devices for con-trolling the mechanical operation of .the ram has been described, other devices suitable for accomplishing this purpose may be utilized and that the present invention is not intended to be limited to the illustrative control means just described.

The present invention, as illustrated in the embodiment thereof, is morey particularly concerned with a method and apparatus for detecting when the reciprocating movement of the stud or bolt I4 and its associated parts is interrupted, is slowed down in some manner or ceases, due to failure of the gun to fire and recoil. These detecting means then control the operation of the solenoid 65 which permits mechanical action of the ram and its control devices. These detecting means may be structurally associated with the reciprocating bolt I4 to detect lack of motion thereof by a current pulsing means such as an interruptor or alternator operated, actuated, driven or otherwise associated with the reciprocating parts of the gun charging mechanism.

In Figure 2 of the drawings a current interrup-ter is illustrated as a'xed elongated commutator bar or frame 15 on which is mounted a series of alternately arranged electrical conducting members 76 and non-conducting members 'Il'. A slidable frame 'I5 is mounted on the guide rods or tubes 21 and is attached to the stud I4 for movement therewith. The frame 'I9 carries a brush or Wiper for alternately contacting the members 'I6 and 'VI while reciprocating with respect thereto. The conducting members 16 and the brush 89 are operatively connected in an electrical circuit about to be described. The members 75 and 'Il preferably are of substantially equal eiective length whereby the period of flow of current and the period of interruption of current are of a substantially equal duration of time. Any suitable number of elements, members or contacts 'I6 and 'I'I may be provided. Instead of using a fixed interrupter bar l5, as illustrated, it will be understood that the stud I4 could carry any suitable linkage for driving a rotatable interrupter, commutator or alternator adapted'to aaoacas be contacted by a stationary brush, Without departing from the scope of the invention.

Referring to Figure 3 of the drawings, thereA is shown a wiring diagram of a preferred electrical detecting and operating circuit or brainf This .circuit is illustrated as a modied bridge type circuit, and will be described in Ydetail hereinafter. The circuit shown is particularly adapted for machine guns installed in airplanes, tanks or other craft wherein the gun may be operated locally or from a remote location. Generally, to accomplish this the electrical devices of the circuitare arranged in three groups designated as the control panel, the relay panel and the gun charger.

The control panel has mounted thereon, a pilot light 85 adapted to vbe illuminated when the gun charger ram |S is operating; a switch `iii having a safety, off and ring position; and a switch 81 for effecting operation of the gun charger at the will of the gunner or operator. A firing or trigger switch 39 is operatively `associated with the control panel, and may be located adjacent the gun or at a remote location where the gunner Aor operator may .centrally control the rng of vone or more machine guns. An electrical heater 90 may be provided for the vessel i6 containing the pressure medium to prevent ,the pressure from dropping below a desired minimum when the vessel is exposed lto Very low temperatures, such .as may be encountered at high .altitudes. The heater circuit may lead to the control panel and preferably has a thermostat EH therein which is operative in response to ltemperatures at which the heater 90 is desired to operate. A source of direct current is supplied by a line 02, conventionally indicated as having a positive polarity. The negative pole of the source of current (not shown) may be suitably grounded and the various circuits v may be respectively grounded at desired points to complete the Apaths through which current may ilow.

The relay panel has mounted thereon three resistance elements 94A, 94B and 04C, the purpose of which will be described hereinafter; a relay 95 adapted to be operated by continuous current and unaffected by rapidly interrupted current; and a second relay Qvadapted to be operated by the relay 95 to close a `circuit adapted to supply current to the pressure medium Valve controlling solenoid E5. Ii desired the relay 96 may be omitted by providing the `relay 95 with contacts for closing the solenoid circuit.

The gun charger has associated therewith-the current interrupter, indicated by the interrupter bar l and the brush 80; a resistance element 04D; a switch 97 for cuttingrout ,the detecting circuit when the ram i9 is operated; and a switch 99 movable into a position for closing the pilot light circuit responsive to the operation of the ram. The solenoid 65 for controlling the pressure medium valve 35 also may be associated with the gun charger and a circuit may pass through the gun charger housing for energizing a ring pin solenoid |00 associated with the iiring mechanism of the gun.

The electrical circuits, illustrated in Figure 3, will now be described. The switch 66 is of the double pole double Ithrow type having a `center 01T position. The switch comprises apairof poles |0| and |02; a pair or" contacts or terminals |04 and |05 adapted to beengaged'by. the poles |0| `and |02, respectively, when the switch is 1in a safety position; and a pair of 4contacts or terminals |06 and |01 adapted tofbe engaged by the poles |0| and |02, respectively, when the switch -is in a firing position. The pole |.0| is electrically connected to the current supply line 92 by a Wire |09, and the terminals |04 and |06 lare electrically connected to each other by a wire i I0 and .to a, wire through which cur.- rent is adapted to pass when the switch 8B is in either of its closed positions.

The wire is connected to a wire ||2 which is connected to one terminal of the thermostatically responsive switch QI. The other terminal of the switch 9| is connected to one terminal of the heater 90, which has its other terminal grounded at Hd. The wire is also connected to a wire ||5 which is connected to one terminal of the manually operable switch 81 and the other terminal cf the switch 8'! is connected by a wire 6 to one terminal of the pressure medium valve controlling solenoid 05, which has its other terminal grounded at The wire also is connected to one terminal of the pilot light 85 by a wire ||9 and the other terminal of the pilot light 85 is connected to one terminal of the pilot light operating switch 99 by a wire |20. The other terminal of the switch 99 is grounded at 12|.

The pole |02 of the switch 86 is adapted to Contact the switch terminals |05 and |01. In thecircuit shown, the terminal |05 is not electrically connected because it is superiiuous, but the terminal |01 is connected to the ring circuit by a wire |22, as described hereafter. The pole |02 is connected to one terminal of the firing or trigger switch 89 by a wire 24 and the other terminal of the switch 80 is connected to the supply line 62, whereby when the switch 86 is in iiring position and the trigger switch is closed, current ows through the iiring circuit by way of the wire |22.

The ring circuit includes a single pole double throw switch |25 which is associated with the relay 9.6 and normally is in position to close the firing circuit, as shown in Figure 3. The switch |25 when in this position, is adapted to permit current to pass from the wire |22 to a wire |26 connected to one terminal of the iiring pin solenoid H50, which has its other terminal grounded l When the relay 96 is operated, the switch |25 is adapted to be moved into its other position to permit current to ow from the wire |22 to a wire |29 connected to the wire IIB leading to the pressure medium valve controlling solenoid 65.

A preferred method for supplying interrupted current to the relay during the normal operation of the gun and continuous current during stoppage or slowingdown of the gun charging mechanism may comprise connecting the relay into a circuit including 4a current supply and an interruptor, in such a manner, that it is normally subject to a rapidly interrupted current by which it is not aiected, and that it is subject to a continuous current when the charging mechanism has stopped for a given period.

A preferred circuit for carrying out this method of `detecting the lack of reciprocating `movement of the gun charging mechanism and for initiating operation of the gun charging ram will'now be described in detail. IThis circuit is illustrated in Figure 3 and is illustrated in simplified form in Figures 4, 5 and 6. Generally, this circuit comprises the current interrupter 15; the brush 80 moved by the reciprocating parts of the gun charging mechanism; the resistance elements A, 94B, 513C and StD; the relay 05; and the cutout switch 91 adapted to render .the circuit ineiective during operation of the ram |55. Electrical energy is adapted to besupplied tothe circuit from the source of direct Vcurrent 92 con- 9 nected through the switch 86 and the firing or trigger switch 89, when in firing position, to the wire |22 which in turn is connected to a wire |30. The path of the current which may pass through the circuit is completed by grounding the brush 80 at I3! and the resistance element 94C at |32 (Figure 3) or by electrically connecting the brush 80 by a wire |34 to the grounding connection at |32 (Figures 4, 5 and 6) In the detecting circuit the resistance elements 94A and 04B each have one terminal connected to the current supply wire |30. These elements have substantially the same electrical resistance, to provide an electrically balanced circuit under certain conditions of operation, which will be de,

scribed hereafter. The other terminal of the element 94A is connected to one terminal of the element QQD by a wire |35 and the other terminal of the element 94D is connected to a wire |36 which is connected to all of the conducting members 76 of the interrupter l5. The other end of the element 94B is connected to one terminal of the element 94C which has its other terminal grounded at |32. The elements 913C and 94D have substantially the same electrical resistance for the reasons described hereafter.

In effect, and as illustrated more particularly in Figures 4, and 6, the elements B and C and the elements A and D, respectively, are connected in series. The respective pairs of elements provide, in effect, parallel circuits leading from the wire to the grounding connections at |32. The relay 95 is connected across these parallel circuits by connecting one terminal of the relay 95 to the wire |35 or the connection between the elements 06A and 04D and connecting the other terminal of the relay 05 to the connection between the elements B and C, indicated at |37.

The relay 95, as previously explained, is of the type which is adapted to be operated by continuous current flowing in either direction, for a predetermined period but is not affected by current which alternates its direction of flow or is interrupted at a frequency higher than a predetermined frequency. Such a relay may be of the socalled time delay type in which a heavy copper ring encircles the core of the relay. When current starts to flow through the coil of such a relay, in either direction, a countervoltage is induced by the short-circuiting copper ring, retarding the build-up of magnetic flux and therefore retarding the operation of the relay. When the current has established itself, however,'the copper short-circuiting ring has no effect and the relay operates in the normal manner. The only effect 0f this ring is to delay the relay operation for a fraction of a second. Thus when alternating current of a suniciently high frequency is applied, the relay is not affected and will not operate because the direction of the current is being reversed so rapidly that the magnetic flux does not have an opportunity to build up.

It has been found that a relay, known as a direct current, series, slow releasing type relay may be utilized. Preferably this relay has an 0D- erating time of about .004 to .25 second and a releasing time of about .020 to .350,second. Such a relay is illustrated on page 8 of Catalogue 4071-B, published February 1940, by American Automatic Electric Sales Company, Chicago, Illinois. Since such relays are generally known and are commercially available, a detailed description of the construction thereof is not believed to be necessary. It will be understood, that while a relay of the foregoing character is preferred, other single throw switch |39 (Figure 3) which normal` ly is in open position and is adapted to be closed by the operation of the relay 95 to close a circuit leading from wire |22 through the coil of the re lay 9S to the grounding connection at |40. Thus, when the switch |39 is closed, current is supplied to the relay 96 to operate the switch |25 which closes thepressure medium valve controlling solenoid circuit to effect operation of the ram |9.

The relay 95, when connected in the circuit just described, is normally supplied with alternating or rapidly reversing current while the gun charging mechanism is reciprocating or is operating to load and fire the gun at its normal speed. The alternation of the direction of flow of the current is accomplished by the circuit, shown in Figures 3, 4, 5 and 6, and the interrupter 'l5 or other suitable device therein in the following manner. -Y

When the brush contacts any one of the current conducting elements 'l5 (Figure 4), current from the wire |30 divides and flows through the resistance elements 04B and 94C to the grounding connection at |32, as indicated by the arrows a. The divided portion of the current ows through the resistance element 94A, the wire |35, the switch 91 (normally closed), the wire |36, oneV of the conducting elements 10, brush 80, and wire |34 to the grounding connection as indicated by the arrows b. The resistance to the flow of current in the path of the arrows a -will be greater than the resistance to the flow of current in the path of the arrows b, whereby a portion of the current in path a will divide out at |37 and pass through the relay in the direction indicated by arrow c. It will be understood that the resistance characteristics of the relay coil are such that they will not impede the ow of current in direction c.

When the brush 80 is moved out of contact with any of the conducting elements 'I6 and contacts any one of the non-conducting` elements Tl or is in a position between the contacts 16 (Figure 5), current flows through the circuit as follows. The current divides at'the wire |30 and a portion thereof flows through the resistance elements 04B and 36C to the grounding connection` |32 as indicated by the arrows a. The other por-VV tion of the current flows through the resistance element 94a as, indicated by the arrows b and through the coil of the relay 95 to |31 as, indie cated by the arrow d, because the circuit leading through the interrupter l5 is broken.

The direction d, as will be noted, is opposite to the direction c, and the direction in which the current flows is rapidly alternated by the rapid movement of the brush/80 from a circuit closing to circuit opening position. Thus, if a sufficient number of conducting elements 16 and alternately arranged non-conducting elements 'Vl are pro# vided in the interrupter and the interrupter brush 30 is reciprocated at a rate of 400 to 1000 strokes' per minute the direction of the current will be alternately reversed at a rate at which the relay S5 will not be operated. For example, if the fre-- quency of current reversal is of a magnitude at `which current flows in either direction for a period of time, shorter than the time required by the relay to build up magnetic iiux, the, relay will not be aifected. The relay will be operated only when the brush 80 stops moving or slows down to an extent where the frequency of the current reversals is relatively low. The latter condition would indicate that the gun is not firing properly. In the event the brush stops while in contact with a conducting element l5, direct current will flow through the relay coil in direction c (Figure 4) If the brush stops while out of contact with an element 16, direct current will flow through the relay coil in direction d (Figure 5).

The operation of the cut-out switch al is illustrated in Figure 6. In the event the detecting devices initiate operation of the ram i 9, the ramming head 24 or a member carried by the head may mechanically engage the switch 9i upon initial movement of the ramrning head 2li and .move it out of its normal position shown in Figures l and 5 and into the position shown in Figure 6, whereupon the kswitch 97 opens the connection between the wires |35 and |35 and connects the wire |36 to the grounding point l I If the brush 80 is out of contact with a conducting element 'i6 of the interrupter, the current will divide at |30 and a portion will now through the resistance elements 94B and MC to the grounding connection |32 and the other portion of the current will low through the resistance element 94A, the wire |35, the resistance element 94D, the wire |35` and the switch 97 to the grounding point illl Since the resistance of element 94A is equal to element 94B, and the resistance of element 94C is equal to element MD, the sum of the resistance of elements 94A and 94D is equal to the sum of the resistance of elements MB and 94C. Therefore, the same proportion of currents flows in paths a and b, whereby the two paths-are balanced and no current flows through the relay 95. Thus when this condition prevails, the relay is insensitive and is not operated. The switch Sl is designed to return by itself or to be returned by the ramming head to its initial or normal inactivate position when the ram is moved into its normal or at rest position, as indicated in Figure 2.

In the event the ram is operated to move the cut-out switch 9T out of its normal position while the brush contacts one of the conducting elements 16, the foregoing result is accomplished in substantially the same manner. The only difierence now is that the current in the path b may ow to either of the grounding. connections l32 and ll to complete the circuit. The circuits indicated by the paths a and b then are again balanced and no current is supplied to the relay 95.

In operation, the gun charger l2 is attached to either side of the machine gun housing H, the pressure medium vessel |65 .is connected to valve 35 by the hose |71 .and the electrical circuits are connected to a source of electric energy, while the main switch 86 is in its oi position. When the switch is in this position, accidental closing the manually operable charging switch 'B1 or the trigger switch 89 will not elect operation of the gun charger or firing of the gun. After the gun and the gun charger is set up for action, either in the eld, in an airplane or other craft, the switch 85 is placed in its safety position. This enables the gun to be charged by closing the Inanually operable charging switch 8l, but accidental closing of the trigger switch 89 will not re the gun. Shortly prior to the time it is desired to rire the gun, the switch 8l is closed to charge the gun and the switch 85 is placed in its ring position, whereby the gun may be red by closing the trigger or firing switch 39 to energize the firing pin solenoid |90.

Once the gun commences ring and the trigger switch 89 is held in closed position by the gunner or operator, the gun continues to nre and the charging mechanism goes through its cycle of operation, namely, feeding, ring and ejecting car-- tridges. During the operation ci the charging mechanism, the current interrupter l5 is operated and the direct current supplied to the detecting devices is converted into substantially rapidly interrupted or alternating current with respect to the relay 95. While the current is thus alternated or interrupted, the continuous current responsive relay is unaffected and does not operate. However, if normal movement of the reciprocating parts of the gun charging mechanism should cease, the current through the relay becomes sufficiently continuous to cause actuation of the relay. Within a fraction of a second, the relay 95 is operated to close the switch |39, whereby current ows through the auxiliary relay 96 to operate the switch 25. The switch |25 cuts out the source of current supplied to .the ring pin solenoid Iil and connects this source of current to the pressure medium valve controlling solenoid 65.

The solenoid 65 is immediately effective to release the latch and lever mechanism, illustrated in Figure 2, which in turn operates the Valve to admit pressure medium to the cylinder 2D of the ram. The ram is then operated to mechanically move the gun charging mechanism through its operating cycle to put the gun in action again. As the ram is operated, the cut-out switch 91 is moved into the position in which it prevents the flow of current through the detecting relay 95 (Figure 6). Also, the pilot switch 9E) is closed so that current ,flows through Vthe pilot light which indicates to the gunner that the automatic gun charger is in operation. When the ram returns to its normal inactive position and the gun is restored to normal iiring the pilot switch S9 and the cut-out switch Ell return to their initial positions under the iniluence of suitable resilient means (not shown). As the gun resumes :firing the solenoids of the relays 95 and 95 become deenergized to permit the switches |39 and |25 to return to their initial positions under the ini-luence of resilient means usually associated with relays of the type employed.

In Figures '7, 8 and 9 a modified circuit is illustrated, for interrupting the current for the detecting mechanism by alternating the direction thereof. The interrupter 15 comprises a series of conducting elements or contacts "I6 and 16', a1- ternately arranged and spaced apart a short distance by insulation, if desired. The contacts 16 are connected by a wire M5 to one terminal of the source of direct current indicated at |30, and the contacts I6 are connected by a wire |46 and a resistance element IMC to the other terminal of the source of current indicated at |32. A slider or brush 8B rides upon a conducting bar or slide 33 connected by a wire |41 'to one terminal of the relay 95. A resistance element l 94A has one terminal connected at |33 to the source of current and has its other terminal connected at |31 to one terminal of a resistance element |94B, which has its other terminal connected at |32 to the other pole of the source of current. The other terminal of the relay is connected at |31.

The relay S5 operates only in response to direct or continuous current of sufficient duration in either direction and the interrupter 15, in conjunction with the circuit as shown, is adapted to effect a rapid reversal of the direct current sup- '16, as shown in Figure 7, a portion of the current iiows through resistance elements IMA and |94B, as indicated by arrows a. Another portion of the current flows through wire |45, contact 76, brush 80, bar 83, and wire |41 to the relay Q5 in the direction as indicated by arrows b.

When the brush 8|) contacts one of the elements 16 as shown in Figure 8, the current ows through resistance element |94A and a portion of the current ows through resistance element I94B, as indicated by arrows a. The current divides at |31 and a portion thereof flows through the relay 95, wire |47, bar 83, brush 80, contact 16', wire |46 and resistance element |940 to the pole |32 of the source of current as indicated by arrows a'.

In the event the gun ceases firing and the brush stops in an intermediate position where it contacts both an element 'i6 and 16', as shown in Figure 9, a portion of the current ows through resistance elements |94A and 94B. Another portion of the current ilows through wire |45 to the interrupter 'l5 where it divides and a portion flows through wire |41 and the relay 95 in the direction of arrow b and the other portion of the divided current ows through the wire |46 and resistance element |940 to the current connection |32, as indicated by the arrow b. The resistance element 94C prevents a direct short circuit and preferably has a resistance slightly greater than the resistance element |94B so that the circuit is unbalanced and current flows through the relay 95.

During the normal firing of the gun the direction of the current is alternately reversed as noted in connection with Figures 7 and 8. If the gun should cease ring and the brush stops in any one of the positions shown in Figures 7, 8 and 9, current will flow continuously in the direction indicated.

From the foregoing description it will be seen that the present invention provides an improved gun charger and improved method of operation.v

The gun charger detecting devices are adapted for machine guns having a relatively high firing speed and quickly detect a failure of operation and return the gun to tiring operation in a minimum period of time. Machine guns equipped with gun chargers in accordance with the invention are adapted to be put in action again in a split second vand the eifective iiring of the gun is not materially decreased even under adverse conditions, whereby the gunner is not endangered by being subjected to enemy fire without being able to return re. The parts of the gun charger are rugged in construction and are adapted to withstand any rough usage to which they may be subjected.

W'hile my invention has been described in connection with a gun charger for automatic machine guns, it will be understood that the principles of my invention may be applied to other mechanisms where it is desired to detect the slowing down or stopping of any mass or parts normally intended to be in motion. For example, a detecting device embodying my invention may be utilized in connection with electrical, pneumatic or hydraulic motors, internal combustion or steam engines, or other mechanisms or devices having parts moving in a circular, linear or curvilinear path.

While my invention resides in certain principles of construction and operation which have been illustrated and described in connection with the accompanying drawings, it will be apparent to those skilled in the art that the invention may be embodied in other forms of construction and modes of operation without departing in any manner from the spirit and scope of the invention, and I therefore do not wish to be strictly limited to the disclosure, but rather to the scope of the appended claims.

I claim:

1. In a gun charger for a machine gun having a reciprocating membenthe combination with said reciprocating member of a normally inactive recharging mechanism for operating the reciprocating member, an electrical control device constructed and arranged to be actuated by a current pulse of a predetermined minimum time interval for rendering said recharging mechanism operative, an energizing circuit for said control device, and currentpulsing means in said circuit adapted to be driven by said reciprocating member, said pulsing means being constructed and arranged to successively energize said control device for intervals less than said minimum time interval during the normal operation of said reciprocating member and to energize said control device for said time interval for rendering said recharging mechanism operative upon failure of normal operation of said reciprocating member.

2. `In the combination of claim 1, means operated by said recharging mechanism upon movement thereof for'rendering said pulsing means ineffective to energize said control device.

3. In the combination of claim 1, said current pulsing means including a rcommutator, and a brush adapted to be connected to said reciprocating member for cooperation with said commutator.

4. In the combination of claim 1, said current pulsing means including a commutator, a brush adapted to be connected to said reciprocating member for cooperation with said commutator, and switch means constructed and arranged for rendering said commutator ineffective when said recharging mechanism is operated.

5. In the combination of claim 1, said energizing circuit comprising two portions, vsaid control device being connected across said portions, said current pulsing means including a current interrupter actuated by said reciprocating member connected in one of said circuit portions.

6. In the combination of claim l, said energizing circuit comprising a bridge having four resistance elements, the total resistance in a pair of adjacent elements being equal to the total resistance in the other pair of adjacent elements, said control device being connected across said pairs of elements and said pulsing means including a current interrupter adapted to be actuated by said reciprocating member for interrupting said bridge at a common junction of said pairs of elements, whereby said control device is energized.

7. In a gun charger for a machine gun having a reciprocating bolt, the combination with said bolt of a normally inactive ram for operating the bolt, an electrical control device including a relay constructed and arranged to be actuated by a current pulse of a predetermined minimum time interval for rendering said ram operative, an energizing circuit for said relay, and current pulsing means in said circuit adapted to be driven by said bolt, said pulsing means being constructed and arranged to successively energize said relay for intervals less than said minimum timeV inten` val during the normal operation of said bolt andv to energize said relay for said time interval for rendering said fam operative upon failure of normal operation of said bolt.

8. In a gun charger for a machine gun having a reciprocating bolt, the combination with said bolt of a normally inactive ram for operating the bolt, an electrical control device including a relay constructed and arranged to be actuated by a current pulse of a predetermined minimum time interval for rendering said ram operative, an energizing circuit for said relay, current pulsing HARRY C. GRANT, JR. 

